On the Capabilities of While, Repeat, and Exit Statements A well-formed program is defined as a program in which loops and if statements are properly nested and can be entered only at their beginning. A corresponding definition is given for a well-formed flowchart. It is shown that a program is well formed if and only if it can be written with if, repeat, and multi-level exit statements for sequence control. It is also shown that if,while, and repeat statements with single-level exit do not suffice. It is also shown that any flowcharts can be converted to a well-formed flowchart by node splitting. Practical implications are discussed. CACM August, 1973 Peterson, W. W. Kasami, T. Tokura, N. well-formed program, while statement, repeat statement, exit statement, go to statement, flowchart, node splitting, software reliability 4.39 4.49 5.29 CA730818 JB January 23, 1978 10:20 AM 2456 5 2456 2456 5 2456 2456 5 2456 2709 5 2456 3004 5 2456 3121 5 2456 1312 6 2456 1425 6 2456 1425 6 2456 308 6 2456 309 6 2456 2138 6 2456 2204 6 2456 2247 6 2456 2356 6 2456 2456 6 2456 2456 6 2456 2456 6 2456 2477 6 2456 2709 6 2456 3186 6 2456