Please help! There is a bug in the program The program should determine whether the second string is a substring of the first. If it is, then the program should print out the first index in which the second string appears in the first. As an example, if the first string is “Hello World” and the second string is “lo”, then the program should print out 3, i.e. the starting index of “lo” in “Hello World.” If the second string is not contained in the first string, then the program should print out -1.   the bug is that my program only works if the second substring begins after a space, Here is the code:  .datastr1: .space 51 #space for str1 (max50 characters including null terminator)str2: .space 51 #space for str2 (max50 characters incl null terminator)msg1: .asciiz "Please enter the first string: " #prompt user to enter str1msg2: .asciiz "Please enter the second string: " #prompt user to enter str2newline: .asciiz "\n" .text.globl mainmain:    # Print sttr1    li $v0, 4    la $a0, msg1    syscall     # Read string 1    li $v0, 8    la $a0, str1    li $a1, 51    syscall     # Print newline    li $v0, 4    la $a0, newline    syscall     # Print message 2    li $v0, 4    la $a0, msg2    syscall     # Read string 2    li $v0, 8    la $a0, str2    li $a1, 51    syscall     #Initialize the counters & pointers    la $t0, str1          # Register for str1    la $t1, str2          # Register for str2    li $t3, 0             # Index counter for str1    move $t2, $t0         # Pointer to keep track of starting position in the first string substringfinder:    lb $t4, 0($t0)        # Load character from the first string    beqz $t4, notfound   # If it reaches end of str1 with no match, not found    lb $t5, 0($t1)        # Load character from the second string    beqz $t5, notfound   #If it reaches end of str2 with no match, not found     # Check if current characters match    beq $t4, $t5, checksubstring     # Check next character in str1    addiu $t0, $t0, 1       addiu $t3, $t3, 1     #Increase index counter by 1    move $t2, $t0         # Update starting position    j substringfinder      # Check next character checksubstring:    addiu $t0, $t0, 1     #Move to next character in the first string    addiu $t1, $t1, 1     #Move to next character in the second string    lb $t4, 0($t0)        #Load next character from the str1    lb $t5, 0($t1)        #Load next character from the str2    beqz $t5, found       # If end of str2, substring found    bne $t4, $t5, reset   # If characters do not match, reset pointers     j checksubstring     #keep checking reset:    move $t0, $t2         # Reset str1 pointer to initial position    la $t1, str2          # Reset str2 pointer    addiu $t2, $t2, 1     # Move start position in str1 by 1    j substringfinder     # Keep searching found:    li $v0, 1             # display integer    move $a0, $t3         # Load index of substring into $a0    syscall    j exit                # Exit the program notfound:    li $v0, 1             #     Display integer    li $a0, -1            # Load -1 to indicate not found    syscall exit:    li $v0, 10            # Exit    syscall

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Please help! There is a bug in the program

The program should determine whether the second string is a substring of the first.

If it is, then the program should print out the first index in which the second string appears in the first.

As an example, if the first string is “Hello World” and the second string is “lo”, then the program should print out 3, i.e. the starting index of “lo” in “Hello World.”

If the second string is not contained in the first string, then the program should print out -1.

 

the bug is that my program only works if the second substring begins after a space,

Here is the code: 

.data
str1: .space 51 #space for str1 (max50 characters including null terminator)
str2: .space 51 #space for str2 (max50 characters incl null terminator)
msg1: .asciiz "Please enter the first string: " #prompt user to enter str1
msg2: .asciiz "Please enter the second string: " #prompt user to enter str2
newline: .asciiz "\n"

.text
.globl main
main:
    # Print sttr1
    li $v0, 4
    la $a0, msg1
    syscall

    # Read string 1
    li $v0, 8
    la $a0, str1
    li $a1, 51
    syscall

    # Print newline
    li $v0, 4
    la $a0, newline
    syscall

    # Print message 2
    li $v0, 4
    la $a0, msg2
    syscall

    # Read string 2
    li $v0, 8
    la $a0, str2
    li $a1, 51
    syscall

    #Initialize the counters & pointers
    la $t0, str1          # Register for str1
    la $t1, str2          # Register for str2
    li $t3, 0             # Index counter for str1
    move $t2, $t0         # Pointer to keep track of starting position in the first string

substringfinder:
    lb $t4, 0($t0)        # Load character from the first string
    beqz $t4, notfound   # If it reaches end of str1 with no match, not found
    lb $t5, 0($t1)        # Load character from the second string
    beqz $t5, notfound   #If it reaches end of str2 with no match, not found

    # Check if current characters match
    beq $t4, $t5, checksubstring

    # Check next character in str1
    addiu $t0, $t0, 1   
    addiu $t3, $t3, 1     #Increase index counter by 1
    move $t2, $t0         # Update starting position
    j substringfinder      # Check next character

checksubstring:
    addiu $t0, $t0, 1     #Move to next character in the first string
    addiu $t1, $t1, 1     #Move to next character in the second string
    lb $t4, 0($t0)        #Load next character from the str1
    lb $t5, 0($t1)        #Load next character from the str2
    beqz $t5, found       # If end of str2, substring found
    bne $t4, $t5, reset   # If characters do not match, reset pointers

    j checksubstring     #keep checking

reset:
    move $t0, $t2         # Reset str1 pointer to initial position
    la $t1, str2          # Reset str2 pointer
    addiu $t2, $t2, 1     # Move start position in str1 by 1
    j substringfinder     # Keep searching

found:
    li $v0, 1             # display integer
    move $a0, $t3         # Load index of substring into $a0
    syscall
    j exit                # Exit the program

notfound:
    li $v0, 1             #     Display integer
    li $a0, -1            # Load -1 to indicate not found
    syscall

exit:
    li $v0, 10            # Exit
    syscall

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