The goto statement in C++ is used to transfer the control of program to some other part of the program. A goto statement used as unconditional jump to alter the normal sequence of execution of a program.
Syntax of a goto statement in C++
goto label; ... ... label: ...
- label : A label is an identifier followed by a colon(:) which identifies which marks the destination of the goto jump.
- goto label: : When goto label; executes it transfers the control of program to the next statement label:.
C++ goto Statement Example Program
#include <iostream>
using namespace std;
int main(){
int N, counter, sum=0;
cout<< "Enter a positive number\n";
cin >> N;
for(counter=1; counter <= N; counter++){
sum+= counter;
/* If sum is greater than 50 goto
statement will move control out of loop */
if(sum > 50){
cout << "Sum is > 50, terminating loop\n";
// Using goto statement to terminate for loop
goto label1;
}
}
label1:
if(counter > N)
cout << "Sum of Integers from 1 to " << N <<" = "<< sum;
return 0;
}
Output
Enter a positive number 25 Sum is > 50, terminating loop
Enter a positive number 8 Sum of Integers from 1 to 8 = 36
In above program, we first take an integer N as input from user using cin. We wan to find the sum of all numbers from 1 to N. We are using a for loop to iterate from i to N and adding the value of each number to variable sum. If becomes greater than 50 then we break for loop using a goto statement, which transfers control to the next statement after for loop body.
- goto statement ignores nesting levels, and does not cause any automatic stack unwinding.
- goto statement jumps must be limited to within same function. Cross function jumps are not allowed.
- goto statement makes difficult to trace the control flow of program and reduces the readability of the program.
- Use of goto statement is highly discouraged in modern programming languages.
Uses of goto Statement
The only place where goto statement is useful is to exit from a nested loops.
For Example :
for(...) {
for(...){
for(...){
if(...){
goto label1;
}
}
}
}
label1:
statements;
In above example we cannot exit all three for loops at a time using break statement because break only terminate the inner loop from where break is executed.