goto

The goto keyword causes program execution to jump to the label specified in the goto statement. The general form of goto is

goto label;
.
.
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label:

All labels must end in a colon and must not conflict with keywords or function names. Furthermore, a goto can branch only within the current function—not from one function to another.

Programming Tip

Although the goto fell out of favor decades ago as a preferred method of program control, it does occasionally have its uses. One of them is as a means of exiting from a deeply nested routine. For example, consider this fragment:

int i, j, k;
int stop = 0;

for(i=0; i<100 && !stop; i++) {
  for(j=0; j<10 && !stop; j++) {
    for(k=0; k<20; k++) {
      // ...
      if(something()) {
        stop = 1;
        break;
      }
    }
  }
}

As you can see, the variable stop is used to cancel the two outer loops if some program event occurs. However, a better way to accomplish this is shown below, using a goto:

int i, j, k;

for(i=0; i<100; i++) {
  for(j=0; j<10; j++) {
    for(k=0; k<20; k++) {
      // ...
      if(k+4 == j + i) {
        goto done;
      }
    }
  }
}

done: // ...

As you can see, the use of the goto eliminates the extra overhead that was added by the repeated testing of stop in the previous version.

Although the goto as a general-purpose form of loop control should be avoided, it can occasionally be employed with great success.