for Loops#

for: Loop Simplification (1)#

while loop approach:

  • Fixed number of runs

  • Counter is initialized

  • Termination condition is evaluated

  • Counter is incremented

This can be done simpler!

for: Loop Simplification (2)#

for (initialization; condition; step)
    ...

  • initialization is evaluated exactly once - before entering the loop

  • condition is evaluated everytime before the loop body is entered. false ⟶ loop termination

  • step is evaluated after the loop body, and before the condition

initialization, condition and step are regular statements

Second Program, revisited#

fahrenheit-for.c#
#include <stdio.h>

int main(void)
{
    int fahr;
    for (fahr = 0; fahr <= 300; fahr = fahr+20)
        printf("%6d\t%6.2f\n", fahr, 5.0/9 * (fahr - 32));

    return 0;
}

  • Wherever there can be a variable, there can be an expression

  • A block ({ and }) is only necessary when the loop body consists of multiple statements

  • 5.0/9 * (fahr - 32) is float because 5.0 is