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